Bumble Bees Near the North Pole

Is that a fact?

It depends, of course, what you mean by “near”: England seems quite near for birds that fly from France across the Channel (la Manche) to reach the English coast, but for insects it sure is a long, long way. The distance from the southernmost edge of Greenland to its northernmost coastline is over 2,600 km, which is (when I heard that bumble bees live in North Greenland) ‘only’ about 800 km away from the North Pole, corresponding to the distance between San Francisco – San Diego or Le Havre in the north and Marseille in the south of France). I was pretty amazed. How can these insects survive there?

It was at the South Korean Ecology Conference that I saw a poster that a scientist by the name of Dr Won Young Lee had put up to report on his research in Greenland as well as in Antarctica. I was curious to meet that person, as there simply aren’t many researchers who have been active in both Arctic and Antarctic environments. When I explained to him where in Greenland I had been and that I had also visited Antarctica nine times, he told me about his research and then happened to mention how surprised he was when in North Greenland at a latitude of nearly 83° N, he had seen bumble bees. I had come across two species of bumble bee (Bombus polaris and B. hyperboreus) in southern Greenland, but had not been aware of the fact that these cold-hardy insects would be distributed to the furthest north of the island. It hadn’t been an interest of my Polar research till then (despite an electrophysiological study of mine in 1981 of the functional properties of the eye of the North Finnish species B.hortorum). 

But now I wanted to know more and requested to join the next expedition to North Greenland (which, however, did not happen as it ‘fell victim’ to the Corona pandemic) to catch some of these bees. Luckily, though, Dr Lee had preserved a Bombus polaris queen bee from North Greenland and with the help of my Iranian colleague Dr Saeed M. Namin (a skillful molecular entomologist) and the support of our Department’s Head (Prof Chuleui Jung), we embarked on a study to investigate the phylogenetic relationships between all known “High Arctic” bumble bee species and to speculate how B. polaris  got to North Greenland and how global warming could possibly affect its distribution and survival there.

We concluded that the female specimen we analysed was most closely related to Canadian populations of B. polaris. Geographic proximity, occurrence of B. polaris on Ellesmere Island 500 km to the west and wind direction were thought likely factors that aided B. polaris to establish itself in North Greenland. A moderately high level of genetic diversity of B. polaris in Greenland was determined reflecting the successful adaptation of the species. However, bumble bees need food and shelter and only the queen overwinters. But where and how in North Greenland’s permafrost-hard soil is there sufficient shelter? And how about pollen and nectar for food? In the broader context of entomological life in the high Arctic, our results on B. polaris allow us to conclude that the survival of pollinating species in the high Arctic under the changing climate scenario depends not only on the weather but also on an individual’s opportunity to continue to locate suitable food sources, which in North Greenland are provided by flowers of the abundant Pedicularis spp., Salix arctica and Ericaceae of the region. Other plants with a northern distribution like Stylophorum sp. and crowberries can be considered pollen and nectar providers, respectively, and are likely to be also visited by B. polaris. Will climate change affect them?

According to one of the foremost Arctic bumble bee researchers (Dr Grigory Potapov), some High Arctic species used to occur much more widely in the past. Will it help us predict the fate of B.polaris? More research may be needed and I’d love to be part of it. My next destination? I hope it’s North Greenland!

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.

How did Ludwig Von Bertalanffy Prevent Fish Species being Over-Exploited?

As more and more consumers turn away from meat, especially that of mammals, they do, however, turn to fish. Consequently, there is increasing pressure on fish stocks in the wild, but a growing opportunity for fish culturists to improve fish rearing facilities. When I was still a student of Fisheries Science in 1967 and lectures I attended dealt with fish stock assessments, catch per unit effort, fish populations, age structures, longevities and survival rates of fishes, time and again Ludwig Von Bertalanffy was mentioned and equations he had developed were quoted and written with chalk on the blackboard (yes, chalk and blackboard in those days). But why were Von Bertalanffy’s calculations so useful and why are they still part of the backbone of fisheries assessments of fish stocks today?

Ludwig von Bertalanffy was born near Vienna in 1901 and although his parents got divorced when he was ten, he did enjoy a good home education until then, when he became a grammar school student. He had the famous anti-Darwinist Paul Kammerer as his neighbour and soon began to apply his mathematical interests to biology and the living world. He is now often regarded as the founder of General Systems Theory, which has inputs from thermodynamics, cybernetics and biology. At the University of Vienna his fields of expertise could be called Theoretical Biology and Philosophy and in 1937 he got a Rockefeller scholarship to work in the USA. When he failed to secure immigrant status, he returned to Vienna in 1938 and joined the Nazi-party. After the war he found living in Austria difficult, moved to the University of London in 1948 and from there two years later to appointments at various American and Canadian universities. He died in 1972 in Buffalo, New York.

In his biological research, Von Bertalanffy was interested in psychology, psychiatry, development and growth phenomena and concluded that thermodynamic principles worked well in closed systems, but not in open systems like those comprising living organisms. He came up with a simple growth equation for biological organisms that models mean length of animals in relation to age:  L(a) = L_∞ [1 – exp (-k(a – a₀))],  where a is age, k is the growth coefficient, a₀ is the value used to calculate size when age is zero and L_∞ is asymptotic size (which means the rate of growth continually decreases as an individual ages but never completely stops). The equation above is the solution of the linear differential equation:  dL/da = k(L_∞ – L) and applicable to organisms that do not cease to grow when adult (unlike, for instance humans, which actually shrink when reaching old age), but keep growing albeit at increasingly slower and smaller rates as they age. Fish are some of these animals and since it is important for fisheries biologists to know at what age (or body length) individuals of a species become reproductive and therefore should not be ‘harvested’ until old enough to have reproduced at least once, it’s obvious that much emphasis has been placed on Von Bertalanffy’s growth curve that relates age to body lengths.

To make this relationship ‘work’, it is crucial to know how old a fish is at any given length. Helping fisheries scientists in this matter are age-rings on the scales of fish (not unlike those that one uses to age trees). The problem is that not all fishes live in climatic zones in which there are distinct seasonal changes that result in age rings on the scales and secondly not all fish species even have scales. In my research with the Polish scientist R. Traczyk, we worked with Antarctic icefish that have no scales and live in constantly ice-cold water. In such cases one uses daily increments of extremely narrow CaCO₃ layers, visible in sectioned ear-stones of the fish examined under the microscope. The layers provide an accurate estimation of the fish’s age that can be correlated with the fish’s total body length. What is then still left to discover is at what age and body length these fish spawn. For that to find out, fish have to be trawled near spawning grounds and females must be measured and examined as to whether they still have mature eggs in their ovaries or had already spawned. Once all the essential data are in, one can use the Von Bertalanffy growth curve to make recommendations to the fishing industry at what size it is ‘safe’ to harvest and market a species without depleting the population of younger and still immature specimens. Although Von Bertalanffy’s work doesn’t save all fish from being ‘fished’, it does help to ascertain that there are still enough youngsters around to maintain the population.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2021.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.